Forming of filaments out of viscose or similar viscous material.



UNITED STATES PATENT OFFICE.

CHARLES A. ERNST, OF LANSDOWNE, PENNSYLVANIA, ASSIGNOR TO SILAS PETTIT, OF

PHILADELPHIA, PENNSYLVANIA.

FORMING OF FILAMENTS OUT OF VISCOSE OR SIMILAR VISCQUS MATERIAL.

Specification of Letters Patent.

Patented Aug. 25, 1908.

,Application filed October 18, 1907. Serial No. 398,088.

To all whom it may concern:

Be it known that I, CHARLES A. ERNST, a citizen of the United States, and a resident of Lansdowne, State of Pennsylvania, .have invented certain new and useful Improvements in the Forming of Filaments Out of Viscose or Similar Viscous Material, of which the following is a full and exact description.

My invention relates to the method of forming filaments out of viscose or similar viscous substances and particularly to the treatment of the Viscose itself, and to the production of filaments therefrom, and the object of my invention is to produce a vis cose which will immediately coagulate into a filament when ejected from the spinneret into a-suitable fixing or coagulating bath.

Further objects of my invention are to hold or retain the cellulose before spinning, dissolved in a solvent which contains less alkali than it has heretofore been thought practicable to employ.

Other objects of my invention will appear in the s ecification and claims below.

In or er to obtain a smooth uniform solution or distention of cellulose sodium Xanthate, sometimes called cellulose Xanthate, which may be the product obtained by treating soda cellulose with carbon bisulfid in the manner referred to in my prior patent, No. 863,793, patented August 20, 1907, it has beenfound advantageous to dissolve the Xanthate in a dilute solution of caustic soda. When a comparatively strong solution of caustic. soda is used, a quick and complete dissolving or distention of the Xanthate therein is effected, but the presence of any considerable amount of caustic soda, or a similar alkali, in the dissolved cellulose Xanthate,

renders the coagulation of the viscose, when,

ejected into a suitable bath through a spinneret, very diflicult and slow. It is difiicult, however, to properly dissolve the cellulose Xanthate in a solution of caustic soda much weaker than a 5% solution. I have found that after the sodium cellulose xanthate or cellulose xanthate has been once dissolved in a caustic solution it will remain in solution or distention, even though a comparatively large amount of the alkaline solvent be neutralized. In other words, I have found that although a suitable amount of caustic soda is necessary to pro )erly dissolve and first form a solution of tile xanthate of cellulose which will spin well, the said Xanthate, when once dissolved, will remain, without coagulation, in a state of solution or distention in a medium which contains a considerably less amount of caustic soda than was originally required to dissolve it. Upon this principle have based a method of making a viscose which has the advantage of being a perfect solution attained by the use'of a solvent having a comparatively great alkalinity but in which the alkali will not prevent a rapid coagulation of the viscose in the setting, or neutralizing or coagulating solution.

In carrying out my invention, I dissolve the sodium cellulose Xanthate or cellulose xanthate in a caustic soda solution,(as for instance a 5% solution, or stronger,) and after thoroughly mixing the same I obtain a perfectly formed solution or distention of the cellulose Xanthate' I then add to thesolution so formed, an acid, or an acid salt, or both to partly neutralize the caustic soda. When so treated the cellulose sodium Xanthate will remain in a perfectly, clear solution, or uniform distention for a day or more, according to the proportion of acid used, notwithstanding the fact that it is held in a medium or solvent which contains less caustic soda than was necessary to eifect that uniform and complete solution, or distention of the Xanthate. Although the cellulose Xanthate solution is in a more unstable condition than it was before the acid was added, it remains in a solution sufliciently long to be conveniently handled and stored before spinning.

I have used acetic acid as an acid and sodium bisulfite asan acid salt for neutralizing the caustic soda, but any acid, or acid salt which does not decompose the Xanthate may be used, as for instance, lactic acid, oxalic acid, sulfurous acid, etc. What I claim, then, is the use of an acid or an acid salt in suflieient quantities to partly neutralize the alkalinity of viscose, and thereby render it more susceptible of being rapidly and easily coagulated in a weak coagulating or neutralizing bath. It is, of course, not necessary to add the acid immediately after the viscose is made, but it may be added any time before the spinning takes place.

' After the viscose has been formed, in the manner above described, it is ejected into a,

- of cellulose or artificial silk.

While I have describd one manner in which I .my invention may be carried out, I do not acid or acidsalts.

Wish to'be construed as limited to'the exact process above set forth, for I may fully treat the xanthate of cellulose in the manner described in my previous patent, No. 863,793, August 20, 1907, before adding thereto the Thus after dissolving the xanthate of cellulose in a solution of caustic soda, I may add thereto a neutral salt such as sodium sulfite, the action of whichis to check the further reaction of the carbon bisulfid upon the soda cellulose which enables me to store the viscose for a com aratively long eriod of time; then shortly efore spinning, may add thereto a suflicient quantity of the acid or the acid salt or both, to neutralize a part of the alkalinity of the solution and facilitatethe rapid spinning of the filaments of' viscose.

It is further obvious that, so far as my im- I proved process goes, it is immaterial when the caustic soda is added to the viscose,;for

. line by using an excess of caustic so the mercerlzmg of the cellulose base.

thus 'roduced, of course, the viscose would ner I 4 the viscose may be rendered stron ly alka- (fa during When disso vein a weaker solution of caustic soda than a 5% solution, but the excess of caustic .soda would, similarly, bring the alkalinity of .the'solution up to the same degree as it would if the rocess were carried out in the manave previously described. In either manner the cellulose would be held sus ended in a solution having a greater alka inity than is desirable for spinning purposes and 'in' carrying out my invention, I add to this -alkaline solution a suflicient quantity of an ..5,0.-'

acid to neutralize or partly neutralize the lkalinityof the same.

Having thus fully described my invention,

hat I claim and desire to protect by Letters Ylfatent 'of the United States is:

- ,The method of forming filaments out of viscose or, similar viscous substance, which consists indissolving the xanthate of cellu- '--lose in a: solvent which is not neutral, parso formed by tially neutralizing the reaction of the said soli fun'st'able, but nevertheless, perfect solution,

vent until the xanthate is retained in a more and then forming a'filament out of the viscose ej ecting in a minute stream into a coagulating 'medlum.

-xanthate in a substantiall tralizing a part of the alkalinity of said solvent without precipitating said xanthate and then spinning the same in a suitable neutralizing solution.

The method of forming filaments out of viscose, which consists in dissolving cellulose xanthate in caustic soda, then adding an acid to the viscose so formed to neutralize a part.

of the caustic soda, and then spinniligthe same in a weak acid bath.

4. Themethod of formingfilaments out of viscose, which consists in distending the 'xanthate of-cellulose in a comparatively strong alkaline solution, then neutralizing the greater art'ofthe alkalinity of' said solvent until t 'e xanthate is held in a solution weaker than that.which was originally required to produce it, and then s mningthe viscose so formed by ejecting it 1n filaments .in a weak neutralizing solutlon;

5. The method of forming filaments out of viscose, which consists in dissolving cellulose I 5% solution of caustic soda, neutralizin t e greater part of the alkalinity of said so vent until the Xanthate is in a solution weaker than was re-l qlpired originally to produce the same, andt on spinnmg the viscose so formed by ejecting it mto a weak acid bath.

6. Themethod of forming filaments out of viscose, or similar viscous substance, thestep which consists indissolving cellulose Xanthate in an alkaline solvent, and then neutralizing a art of thealkalim'ty'of the said solvent wit out precipitating .the'said xanthate.

7. The. method of forming filaments out of viscose, which consists in dissolvin cellulose xanthate in an alkaline solvent, ad ing thereto a neutral-salt, then neutralizing a part'of the alkalinity of said solvent Without precipitating said xanthate, and then spinning the same in a suitable neutralizing solution.

8. The method of forming filaments out of viscose, which consists in dissolving cellulose xanthate in an alkaline solvent, then neutralizing a part of the alkalinit without precipitating said xanthate and t en ejecting it in a minutastream into a coagulating medium.

9. The method of forming filaments out of viscose or similar viscous substances, which consists in dissolving the xanthate of cellulose in an involatile solvent which is not neutral in its reaction, partially neutralizing the reaction of. said solvent without substantially aflecting the chemical constituency of the said xanthateand then forming a filament out of said niscose b ejecting it a minute stream' into "a coagu ating medium.

10. In the method of forming filaments seems r p. ,l '3' out of viscose or similar viscous substances, hand this seventeenth day of October, A. D.

the step which consists in dissolving the cellu- 1907. i lose base in a solution which is not neutral and then partially neutralizing the reaction 1 of the resulting. solution without precipitat- Witnesses:

ing said base. 4 g ,o ALSTON' B. MOULTOiI; I witness whereof I have hereunto set my ALEXANDER} PARK.

CHARLES A. ERNST. 

